WO2012045806A1

WO2012045806A1 - Method for producing monomer compositions, and use thereof for producing a molded polyamide part

Info

Publication number: WO2012045806A1
Application number: PCT/EP2011/067446
Authority: WO
Inventors: Philippe Desbois; Dietrich Scherzer; Andreas Wollny; Andreas Radtke; Axel Wilms; Martin Klatt; Volker Warzelhan
Original assignee: Basf Se
Priority date: 2010-10-07
Filing date: 2011-10-06
Publication date: 2012-04-12
Also published as: CN103237832A; JP5857055B2; BR112013008416A2; KR20130118326A; KR101855544B1; CN105601911B; MY163168A; CN105601911A; EP2625215A1; JP2013538928A; BR112013008416B8; EP2789641A1; EP2625215B1; BR112013008416B1; EP2789641B1; CN103237832B

Abstract

The invention relates to a method for producing an activated monomer composition containing at least one lactam and/or lactone, a catalyst, and an activator, wherein said method enables the produced monomer composition to be stored because the monomer composition is stable with respect to polymerization. Said monomer composition is used, among other things, for producing a molded polyamide part by means of ring-opening, anionic polymerization.

Description

Process for the preparation of monomer compositions and their use for the production of a polyamide molding

description

The present invention relates to a process for preparing an activated monomer composition comprising a lactam and / or lactone, a catalyst and an activator. The monomer composition prepared by the process according to the invention is initially stable to the polymerization and can be used at a later time for the polymerization.

Furthermore, the present invention relates to a process for producing a polyamide molding, in particular a cast polyamide molding, by ring-opening, anionic polymerization using an activated monomer composition.

Polyamide molded parts, in particular fiber-reinforced polyamide molded parts, have been increasingly used in recent years as materials in replacement of metallic materials, for example in the automotive industry, and can replace both parts in the power train and metal body parts. It is often advantageous in the production of a polyamide molding to fill the mold with a monomer melt rather than a polymer melt. Due to the lower viscosity z. B. in the case of a filled or fiber-reinforced molding higher Füllgrade be realized.

Lactams, such as, for example, caprolactam, laurolactam, piperidone and pyrrolidone, but also lactones, such as caprolactone, can be polymerized in a base-catalyzed anionic polymerization reaction in a ring-opening manner. For this purpose, usually a melt of lactam and / or lactone containing an alkaline catalyst and a so-called activator (also co-catalyst or initiator) at temperatures of about 150 ° C polymerized.

The customary, known, activated anionic polymerization of lactams to polyamides is preferably carried out on an industrial scale in such a way that on the one hand a solution of catalyst in lactam and on the other hand a solution of activator in lactam are prepared. Both solutions are preferably composed such that mixing in the same ratio gives the desired total formulation. Thus, DE-A 1 420 241 describes an anionic polymerization of lactams in the presence of potassium hydroxide as catalyst and using 1,6-bis (N, N-dibutylureido) hexane as activator. An activated anionic lactam polymerization using sodium caprolactam is described for example in Polyamides, Kunststoff Handbuch, Vol. 3/4, ISBN 3-446-16486-3, 1998, Carl Hanser Verlag, pp. 49-52 and Macromolecules, Vol 32, No.23 (1993), p. Further prior art is also described in DE-A 10 2008 000 352.

As already described in the prior art, the anionic polymerization of lactams and lactones can be carried out in a reaction casting or reaction injection molding process wherein the catalyst and further additives are added to the lactam and / or lactone melt during the polymerization process. The prior art processes have the disadvantage that the processor, before filling the casting or mixing apparatus, each time elaborately with absolute exclusion of water defined amounts of catalyst, activator or other additives in molten lactam, e.g. Caprolactam, must stir. Since the anionic polymerization of lactams and lactones must be carried out in the absence of oxygen, carbon dioxide and water in order to avoid premature termination of the polymerization, carrying out a polymerization in a reaction molding or reaction injection molding process involves considerable technical effort.

It would therefore be advantageous in terms of process economy, if for the production of polyamide molded parts, a composition could be used, which already contains the lactam and / or lactone monomer, the catalyst and the activator and optionally further additives, and which could be polymerized directly in the mold, for example by raising the temperature.

An object of the present invention is to provide a process for producing a monomer composition containing lactams and / or lactones, which can be polymerized as such without further addition of catalysts and / or activators. In addition, an object of the present invention is to provide a process for producing a polyamide molded article, which is easy and inexpensive to perform using conventional simple molding processes, and obtained with the polyamide molded articles of high quality and with a low content of residual monomer can be. Another object of the present invention is to provide a simple process that results in improved quality cast polyamide molded parts. In addition, the content of monomers in the final product should be as low as possible, which z. B. expressed in a lower odor. In addition, the simplest possible processing should be achieved. The process should be carried out, for example, using standardized, low-cost processing machines. As described in the prior art, the anionic polymerization of lactates, in particular as a result of the addition of an activator (for example an isocyanate, acid halide or acid anhydride), takes place very rapidly (rapid polymerization) and even at very low temperatures close to the melting temperatures of the corresponding lactams ,

It has surprisingly been found that stable monomer compositions can be prepared which contain an initiator and a catalyst in addition to the lactam and / or lactone monomer. These monomer compositions are initially stable to polymerization. For example, such a monomer composition can be obtained by melting and cooling the components, with rapid crystallization of the monomers (lactam and / or lactone) in particular being crucial. These monomer compositions can be stored for several months and used later for polyamide production. The polymerization of such a monomer composition may be accomplished by use of simple methods such as injection molding or casting, especially at temperatures in the range of 150 to 200 ° C.

The present invention relates to a process for preparing a composition (C) comprising the following components: i) at least one monomer (M) selected from lactams and

lactones;

ii) at least one catalyst (K);

iii) at least one activator (A); comprising the following steps Mixing the components (M), (K) and (A) and optionally other components at a temperature of 50 to 200 ° C, in particular from 50 ° C to 160 ° C, preferably from 50 ° C to 100 ° C;

Cooling the mixture obtained under step a) to a temperature of 0 ° C to 60 ° C, preferably 0 ° C to 35 ° C, particularly preferably 0 ° C to 25 ° C;

optional granulation of the cooled mixture.

The monomer composition obtained by the process described constitutes a valuable intermediate product which can be stored, transported and handled as such, for example in the form of powder, granules or capsules. This ready-mixed solid monomer composition is characterized by easy handling. In addition, no elaborate reactive polymerization process comprising two components, such as, for example, RTM (Reaction Transfer Molding) or RIM (Reaction Injection Molding), is necessary for processing (polymerization).

Due to the low viscosity of the monomer composition used at the processing temperatures (monomer melt), a very good penetration of matrix materials present in the mold (for example fillers or fiber mats) can be achieved. Thus, the polyamide part produced by means of the process according to the invention can have a very high filling or pulp content of about 50 to 90% by weight.

In general, it is advantageous to remove contaminants, e.g. Keep water, carbon dioxide and oxygen in composition (C) as low as possible. Therefore, in particular, all components used should be dry and free of oxygen and carbon dioxide, or contain as small amounts of it. The mixing of the components (M), (K) and (A) (and optionally further components) preferably takes place under an inert gas atmosphere (for example under nitrogen). In particular, the steps a) to c) are carried out with substantial exclusion of oxygen, carbon dioxide and water.

The mixing of the components in step a) is preferably carried out at a temperature greater than or equal to the melting temperature of the monomer (M) or of the monomers (M) used and at a temperature of 200 ° C., preferably below 160 ° C., preferably below 120 ° C, particularly preferably below 100 ° C. Further preferred is a temperature below 90 ° C. The selected temperature range in step a) also depends on the choice of the monomer (M) or of the monomers (M). The mixing of the components in step a) can be carried out in a discontinuous or continuous process in known and suitable apparatuses known to those skilled in the art. The mixing of the components in step a) can be carried out, for example, continuously and / or batchwise in a stirred tank. The mixing of the components in step a) can be carried out, for example, continuously in an extruder.

After mixing the components in step a), it is preferable to cool the monomer melt as quickly as possible (rapid crystallization of the monomer). In particular, the cooling of the mixture in step b) to a temperature of 0 ° C to 60 ° C, preferably from 0 ° C to 35 ° C, more preferably 0 ° C to 25 ° C within a period of 1 second to 5 minutes, preferably in the range of 1 to 60 seconds. The cooling of the mixture obtained in step a) can be effected in particular by a cold gas stream (for example a nitrogen gas stream of 0 ° C.) or a so-called "cold-disk process".

Suitable lactams are, in particular, caprolactam, piperidone, pyrrolidone, laurolactam or mixtures thereof, preferably caprolactam, laurolactam or mixtures thereof. Particular preference is given to using caprolactam or laurolactam as monomer (M). Furthermore, it is possible to use as monomer a lactone or a mixture of lactam and lactone. As lactones, for example, caprolactone or butyrolactone can be used. The amount of lactone as comonomer preferably does not exceed 40% by weight, based on the total monomer. The proportion of lactone as comonomer is preferably not more than 10% by weight based on the total monomer. In a preferred embodiment of the invention, only lactams are used as monomers (M). Unless indicated otherwise, the data in% by weight refers to the total amount of the composition. In particular, at least one monomer selected from the group consisting of caprolactam, piperidone, pyrrolidone, laurolactam and caprolactone is used as the monomer (M).

In a preferred embodiment, the composition (C) contains caprolactam (especially as the sole monomer (M)) and the mixing of the components in step a) takes place at a temperature of 70 ° C to 160 ° C, preferably from 70 ° C to 120 ° C, more preferably from 70 ° C to 100 ° C, further preferably from 70 ° C to 90 ° C. In a preferred embodiment, the composition contains (C) lauryl lactam (especially as the sole monomer (M)) and the mixing of the components in step a) is carried out at a temperature of 150 ° C to 200, especially from 150 ° C to 160 ° C.

In the process according to the invention, preference is given to using a catalyst (K) which is a common catalyst for anionic polymerization. In the context of the present invention, a catalyst for the anionic polymerization is understood as meaning a compound which allows the formation of lactam anions. Lactam anions per se can also act as a catalyst.

Such catalysts are known for example from polyamides, Kunststoffhandbuch, 1998, Carl Hanser Verlag. In the context of the present invention, a catalyst is preferably selected from the group consisting of sodium caprolactamate, potassium caprolactamate, bromide magnesium caprolactamate, chloride magnesium caprolactamate, magnesium biscaprolactamate, sodium hydride, sodium, sodium hydroxide, sodium methoxide, sodium ethanolate, sodium propanolate, sodium butanolate, potassium hydride , Potassium, potassium hydroxide, potassium methoxide, potassium ethanolate, potassium propoxide and potassium butoxide, preferably consisting of sodium caprolactamate, potassium caprolactamate, bromide magnesium caprolactamate, chloride magnesium caprolactamate, magnesium biscaprolactamate, sodium hydride, sodium, sodium hydroxide, sodium ethanolate, sodium methoxide, sodium propoxide, sodium butoxide, potassium hydride, potassium, potassium hydroxide, Potassium methoxide, potassium ethanolate, potassium propoxide and potassium butoxide.

Particular preference is given to using a catalyst (K) selected from the group consisting of sodium hydride, sodium and sodium caprolactamate; particular preference is given to the use of sodium caprolactamate and / or a solution of sodium caprolactamate in caprolactam (for example Bruggolen® (BASF, DE) C100, 18% by weight of sodium caprolactamate in caprolactam).

The molar ratio of monomer (M) to catalyst (K) can be varied within wide limits, it is generally from 1: 1 to 10,000: 1, preferably from 10: 1 to 1000: 1, particularly preferably from 20: 1 to 300: 1.

In the composition (C) which is prepared according to the process of the invention, in particular at least one activator (A) is contained for the anionic polymerization. In the context of this invention, an activator for the anionic polymerization is a lactam which is N-substituted by electrophilic radicals (for example a Acyllactam). As activator (A) it is also possible to understand precursors for such activated N-substituted lactams which, together with the monomer (M), form an activated lactam in situ. The amount of activator typically defines the number of chains growing as each activator molecule is the initial member of a polymer chain

represents. As activator (A) is generally suitable isocyanates, acid anhydrides and acid halides or their reaction products with the monomer (M).

Suitable activators (A) are aliphatic diisocyanates such as butylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, undecamethylene diisocyanate, dodecamethylene diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), aromatic diisocyanates such as tolylene diisocyanate, isophorone diisocyanate, 4,4'-methylenebis (phenyl) isocyanate or polyisocyanates (for example isocyanates of hexamethylene diisocyanate, Basonat HI 100 / BASF SE), allophanates (for example ethylallophanate). In particular, mixtures of the compounds mentioned can be used as activator (A).

Also suitable as activators (A) are aliphatic diacid halides, such as butylene diacid chloride, butylene diacid bromide, hexamethylene diacid chloride, hexamethylene diacid bromide, octamethylene diacid chloride, octamethylene diacid bromide, decamethylene diacid chloride, decamethylene diacid bromide, dodecamethylene diacid chloride, dodecamethylene diacid bromide, 4,4'-methylene bis-

(cyclohexylic chloride), 4,4'-methylenebis (cyclohexylic acid bromide); as well as aromatic diacid halides, such as toluylmethylenedioic acid chloride, toluylmethylenebisic acid bromide, isophorone diacid chloride, isophorone diacid bromide, 4,4'-methylenebis (phenyl) acid chloride, 4,4'-methylenebis (phenyl) acid bromide. In particular, mixtures of the compounds mentioned can be used as activator (A).

Particular preference is given to a process, characterized in that at least one compound selected from the group consisting of aliphatic diisocyanates, aromatic diisocyanates, polyisocyanates, aliphatic diacid halides and aromatic diacid halides is used as activator (A).

In a preferred embodiment, at least one compound selected from hexamethylene diisocyanate, isophorone diisocyanate, hexamethylene diacid bromide, hexamethylene diacid chloride as the activator (A); hexamethylene diisocyanate is particularly preferably used.

The activator (A) can be both the pure substance as described above or, preferably, a solution of the activator in a solvent, for example in N-methylpyrrolidone. The molar ratio of monomer (M) to activator (A) can be varied within wide limits and is generally from 1: 1 to 10,000: 1, preferably from 10: 1 to 2,000: 1, particularly preferably from 20: 1 to 1,000 1. In particular, the present invention relates to a method as described above, characterized in that the composition (C) contains at least one further component selected from fillers and / or reinforcing materials (F), polymers (P) and other additives (Z ). The addition of these additional components can be done at any step in the process of making composition (C), for example, before or together with the addition of catalyst (K) and / or activator (A).

The composition (C) may contain one or more polymers (P). The composition (C) may contain, for example, a polymer and / or oligomer which forms in situ by polymerization of the monomers contained in the composition. This optionally contained polymer (P) is contained, for example, in an amount of 0 to 40 wt .-%, preferably from 0 to 20 wt .-%, particularly preferably in an amount of 0 to 10 wt .-%.

In addition, the composition (C) may contain one or more polymers (P) which are added to the composition in the form of a polymer. For example, this added polymer may contain groups suitable for forming block and / or graft copolymers with the polymer formed from the monomers (M). Examples of such groups are epoxy, amine, carboxyl, anhydride, oxazoline, carbodiimide, urethane, isocyanate and lactam groups.

In addition, it is possible to improve the product properties, compatibilities of the components and viscosity of the composition (C) at least one polymer (P) to be added selected from the group consisting of polystyrene, styrene copolymers, such as styrene-acrylonitrile copolymers (SAN ), Acrylonitrile-butadiene-styrene copolymers (ABS) or styrene-butadiene copolymers (SB), polyphenylene oxide ethers, polyolefins, such as, for example, polyethylene (high-temperature polyethylene (HTPE), LTPE (low-temperature polyethylene)). ), Polypropylene or polybutene-1, polytetrafluoroethylene; Polyester, such as

Polyethylene terephthalate (PET); polyamides; Polyethers such as polyethylene glycol (PEG), polypropylene glycol or polyethersulfones (PESU or PES); Polymers of vinyl groups include monomers such as polyvinyl chloride, polyvinylidene chlorides, polystyrene, toughened polystyrene, polyvinylcarbazole, Polyvinyl acetate or polyvinyl alcohol; Polyisobutylenes, polybutadiene and polysulfones. It is furthermore possible to use copolymers as polymer (P) which consist of the monomer units of the abovementioned polymers. The addition of polymers can be carried out in each step of the process of preparation of the composition (C), for example before or together with the addition of catalyst (K) and / or activator (A). In particular, the addition of polymer may serve to adjust the viscosity of the composition (C). The polymer (P) may for example be dissolved or dispersed in the monomer.

In the event that the polymer / polymers (P) are present dissolved in the monomer, the proportion of polymer (P) in the composition (C) is preferably less than 40% by weight. In the event that the polymer (s) are dispersed in the monomer, the proportion of polymer (P) in the composition (C) is preferably less than 60% by weight.

The composition (C) may further contain a crosslinking monomer. A crosslinking monomer may be a compound containing more than one group which can be copolymerized with the monomer (M). Examples of such groups are epoxy, amine, carboxyl, anhydride, oxazoline, carbodiimide, urethane, isocyanate and lactan groups. Suitable crosslinking monomers are, for example, amino-substituted lactams such as aminocaprolactam, aminopiperidone, aminopyrrolidone, aminolauryllactam or mixtures thereof, preferably aminocaprolactam, aminopyrrolidone or mixtures thereof, particularly preferably aminocaprolactam.

In a preferred embodiment, the composition (C) contains at least one filler and / or reinforcing material (F). Suitable fillers and / or reinforcing materials (F) are organic or inorganic fillers and / or reinforcing materials (F). For example, inorganic fillers, such as kaolin, chalk, wollastonite, talc, calcium carbonate, silicates, titanium dioxide, zinc oxide, graphite, graphenes, glass particles, (eg glass spheres), nanoscale fillers (such as carbon nanotubes carbonanotubes), carbon black, phyllosilicates, nanoscale Phyllosilicates, nanoscale alumina (Al ₂ O ₃ ), nanoscale titanium dioxide (TiO ₂ ) and nanoscale silicon dioxide (SiO ₂ ) are used.

Further preferred is the use of fibrous materials as filling and / or reinforcing material (F). The fillers and / or reinforcing materials (F) are usually selected from the group comprising minerals in customary for thermoplastic applications grain size such as kaolin, chalk, wollastonite or talc, carbon or glass fibers, e.g. As milled glass fibers and textile structures (fabric and scrim) of unidirectional fibers, preferably glass and carbon fibers. As a size for the fillers or reinforcing agents, the same size as for use in the thermoplastic to be processed polyamide can be used.

For example, one or more fibrous materials selected from known inorganic reinforcing fibers such as boron fibers, glass fibers, carbon fibers, silica fibers, ceramic fibers and basalt fibers may be used; organic reinforcing fibers such as aramid fibers, polyester fibers, nylon fibers, polyethylene fibers; and natural fibers such as wood fibers, flax fibers, hemp fibers and sisal fibers. Particularly preferred is the use of glass fibers, in particular chopped glass fibers, carbon fibers, aramid fibers, boron fibers, metal fibers or potassium titanate fibers.

The fibers mentioned can be used in the form of short fibers, long fibers or as a mixture of short and long fibers. In this case, the short fibers preferably have an average fiber length in the range of 0.1 to 1 mm. Further preferred are fibers having an average fiber length in the range of 0.5 to 1 mm. The long fibers used preferably have an average fiber length of more than 1 mm, preferably in the range of 1 to 50 mm.

In particular, it is also possible to use mixtures of the stated fillers and / or reinforcing substances (F). Particular preference is given to selecting fillers and / or reinforcing materials (F) as glass fibers and / or glass particles, in particular glass beads.

The composition (C) prepared in the above-described process preferably contains 30 to 90% by weight, especially 30 to 80% by weight, preferably 30 to 50% by weight, more preferably 50 to 90% by weight at least one filling and / or reinforcing material (F).

In a preferred embodiment, the composition (C) may contain further additives (Z). Preferably, the additives (Z) in an amount of 0 to 5 wt .-%, preferably from 0 to 4 wt .-%, particularly preferably from 0 to 3.5 wt .-% in the composition. As additives (Z) it is possible to use, for example, stabilizers, such as copper salts, dyes, antistatic agents, fillers, stabilizers, surface improvers, siccatives, mold release agents, release agents, antioxidants. tien, light stabilizers, PVC stabilizers, lubricants, flame retardants, blowing agents, impact modifiers and nucleating agents are added.

Preferably, the composition (C) contains as additive (Z) an impact modifier, in particular a polydiene polymer (for example polybutadiene, polyisoprene) containing anhydride and / or epoxy groups. In particular, the polydiene polymer has a glass transition temperature below 0 ° C., preferably below -10 ° C., particularly preferably below -20 ° C. The polydiene polymer may be based on a polydiene copolymer with polyacrylates, polyethylene acrylates and / or polysiloxanes and prepared by the usual methods (e.g., emulsion polymerization, suspension polymerization, solution polymerization, gas phase polymerization).

The optional addition of fillers and / or reinforcing materials (F) and further additives (Z) may be carried out at any stage in the production process of composition (C), for example before or together with the addition of catalyst (K) and / or activator (A).

The present invention further relates to the use of a composition (C) obtainable by a process according to the invention for producing a polyamide molding described above.

The present invention also relates to a process for producing a polyamide molding, in particular a cast polyamide molding, by anionic polymerization, wherein at least one monomer (M1) selected from lactams and lactones (preferably a cyclic lactam) is used for the polymerization which has been processed into a granulate with at least one additive (X1) before the beginning of the polymerization and in which case the granules containing at least one monomer (M1) are polymerized, the mixture of monomer (M1) with additive (X1) being optional in solid form or melt before or during the polymerization with at least one further monomer (M2) selected from lactams and lactones (preferably a cyclic lactam) and / or at least one further additive (X2) is mixed. In a preferred embodiment of the invention, the step of polymerizing the at least one monomer (M1) selected from lactams and lactones (preferably a cyclic lactam (M1)) directly follows the preparation of the granules from at least one monomer (M1) (preferred a cyclic lactam (M1)) and at least one additive (X1). The production of granules from at least one monomer (M1) (preferably a cyclic lactam) and at least one additive (X1) is also referred to herein as "packaging" or "preforming". The at least one monomer (M1) (preferably a cyclic lactam) provided with at least one additive (X1) can thus be processed directly into a granulate (or comparable solid particles) in a lactam production plant. This granulate can then be used by the processor for example for the production of a cast polyamide molding and, in contrast to the processes known from the prior art, does not have to be re-provided with additives. The addition of further additives remains as an option.

The term "granules" also means other "prefabricated" particles of a size between 1 mm and 20 mm, preferably an average size of 2 to 15 mm and particularly preferably particles of a mean size of 4 mm to 10 mm. The particles can have different shapes. They may be, for example, barrel-shaped, spherical or even flaky.

In one embodiment of the invention, the optional step of mixing with a further monomer (M2) selected from lactams and lactones (preferably lactam) and / or at least one further additive (X2) is carried out.

In a further embodiment, the optional step of mixing with a further monomer (M2) and / or at least one further additive (X2) is not carried out.

In a preferred embodiment of the process according to the invention, the at least one additive (X1) and the optional further additive (X2) are each independently selected from the group comprising catalysts and activators. As catalysts (K) and activators (A), the compounds mentioned above in connection with the process for the preparation of a composition (C) can be used.

Further objects of the present invention are also a cast polyamide molding, preparable by the process according to the invention, and a solid caprolactam preparation, the at least one additive (X1) in amounts of <90 wt .-%, preferably <60 wt .-% and especially preferably contains <40 wt .-%. Lactams, such as ε (epsilon) -caprolactam, can easily be provided with additives and / or additives (Z) during the preparation, for example with the abovementioned additives (Z), catalysts (K) and activators (A). , in particular with dyes, drying agents, activators or catalysts, chain extenders, stabilizers or impact modifiers.

It is also possible to choose other compositions, for example to meter a prefabricated activator and catalyst melt into a lactam melt, to which further additives can also be added in a further step.

In a preferred embodiment of the method according to the invention, the processing of the at least one monomer (M1) selected from lactams and lactones (preferably at least one cyclic lactam) with the at least one additive (X1) to a granulate by mixing the components in the dry state.

Frequently, the anionic polymerization z. For example, it is possible to melt each monomer component (normally 2 components (M1) and (M2)) with exclusion of moisture, one component catalyst (eg lactamate) and another component the activator (eg. B. isocyanate derivative), and then mixed with stirring with a normal agitator or a suitable mixing machine, the two components. In this case, other additives may be added, for example 3 to 50 wt .-%, preferably 8 to 18 wt .-% impact modifier, stabilizers, flame retardants or other additives.

The casting polymerisation apparatus should preferably, for each melt individually, have a melting circuit up to the casting head, by means of which the melt in the hoses and lines is kept in motion by continuous pumping. However, this cycle is not absolutely necessary for carrying out the method according to the invention.

Suitable monomers (M1) and / or (M2) are the abovementioned monomers (M), preferably cyclic lactams having 6 to 16 carbon atoms, particularly preferably laurolactam and particularly preferably ε (epsilon) -caprolactam. Here, the monomer (M1) and the monomer (M2) may be the same or different.

Likewise, the additive (X1) and the additive (X2) may be the same or different. Additional additives (Z) can also be used as described above. In particular, the above-mentioned fillers and / or reinforcing materials (F) can be used, wherein the fillers and / or reinforcing materials (F) are each added independently before the polymerization as a further additive or during the polymerization.

Fillers and / or reinforcing materials (F) can be used as described above. The fillers and / or reinforcing materials (F) are preferably selected from the group consisting of minerals in customary grain size for thermoplastic applications, for example kaolin, chalk, wollastonite or talc, carbon fibers or glass fibers, eg. As milled glass fibers and textile structures (fabric and scrim) of unidirectional fibers, preferably glass and carbon fibers. As a size for the fillers or reinforcing agents, the same size as for use in the thermoplastic to be processed polyamide can be used.

As the catalyst (K), at least one of the compounds mentioned above in relation to the component (K) can be used. It is preferably an alkali metal or alkaline earth metal lactamate, preferably as a solution in lactam, particularly preferably sodium caprolactamate in ε (epsilon) -caprolactam.

As the activator (A), at least one of the compounds mentioned above in relation to the component (A) can be used. The activator (A) is preferably N-acyl lactams or acid chlorides or, preferably, aliphatic isocyanates, more preferably oligomers of hexamethylene diisocyanate. Activator (A) can be both the pure substance and preferably a solution, for example in N-methylpyrrolidone.

Further additives (Z) and / or additives (X) may be the additives (Z) mentioned above in connection with the process for the preparation of a composition (C). For example, the additives (Z) are to be impact modifiers, flame retardants, nucleating agents, dyes, fillers, stabilizers, surface improvers, siccatives and mold release agents. Preferred embodiments of the invention are also unfilled, filled and / or reinforced polyamide compositions prepared by anionic polymerization of a mixture (composition (C)) containing (or consisting of): a) from 10 to 95% by weight of at least one monomer (M) selected from lactams and lactones; preferably 40 to 95% by weight of cyclic lactam having 6 to 15 carbon atoms in the ring, preferably laurolactam and particularly preferably ε (epsilon) -caprolactam, or mixtures of these lactams, b) 0.8 to 8% by weight of catalyst (K), Preferably, a mixture of about 15 to 20 wt .-% lactamate salt, including preferably sodium lactamate, in ε (ε-caprolactam), c) 0.5 to 5 wt .-% activator (A), preferably aliphatic isocyanates or N- Acyl lactams, d) 1 to 90, preferably 1 to 88 wt .-%, preferably 1 to 50 wt .-%, preferably 3 to 30 wt .-%, particularly preferably 5 to 15 wt .-% filler and / or or reinforcing materials (F), preferably glass fibers, including short glass fibers, ground carbon fibers and textiles of glass and carbon fibers, e) 0 to 20% by weight of other additives and / or additives (Z) such as impact modifiers, flame retardants, nucleating agents, dyes , Filling oils, stabilizers, surface improvers, siccatives or mold release agents.

In this case, one or more of components b), c) and d) are incorporated already during the preparation into the cyclic lactam a), which offers advantages in the processing of these lactams into polyamides.

In a preferred embodiment, the present invention relates to a process for producing a polyamide molded article, wherein a composition (C) can be obtained (or obtained) by a method described above (a process for producing a composition (C)) by heating to a temperature from 120 ° C to 250 ° C is polymerized.

In general, it is advantageous to keep impurities, such as water, carbon dioxide and oxygen, which can lead to a termination of the anionic polymerization, as low as possible. Therefore, in particular, all components used should be dry and free of oxygen and carbon dioxide. Preferably, the polymerization is carried out with substantial exclusion of oxygen, carbon dioxide and water. More particularly, the present invention relates to a process for producing a polyamide molded article as set forth above, comprising the steps of: i) melting the composition (C) at a temperature of 50 ° C to 200 ° C; in particular from 50 ° C to 160 ° C, preferably from 50 ° C to 100 ° C; j) filling the molten composition (C) into a tool cavity; k) polymerization of the composition (C) by heating to a temperature of 120 to 250 ° C.

The melting of the composition (C) is preferably carried out at a temperature greater than or equal to the melting temperature of the monomer (M) or monomers used (M) and under a temperature of less than 160 ° C, preferably less than 150 ° C, preferably less than 120 ° C, particularly preferably below 100 ° C, more preferably below 90 ° C. The selected temperature range in step a) thus depends on the choice of the monomer (M) or of the monomers (M). The molten composition (C) may be filled into a mold cavity by a suitable molding method (e.g., injection molding, casting method) and polymerized therein by raising the temperature.

Preferred is a method for producing a polyamide molding as stated above, wherein the mold cavity before filling the molten composition contains at least one filler and / or reinforcing material (F). In a preferred embodiment, the tool cavity contains a fiber fabric and / or a fiber network, for example a glass fiber mat and / or a glass fiber network. It is also possible to fill a filler and / or reinforcing material (F) together with the molten composition (C) in the mold cavity. This can be done by known methods (for example in an injection molding device or molding device). The optionally added filler and / or reinforcing material (F) can be selected from the fillers and / or reinforcing materials (F) mentioned above in connection with the process according to the invention for the preparation of a composition (C).

With the aid of the method according to the invention, it is possible to produce polyamide molded parts with a high proportion of fillers and / or reinforcing materials (F). par- Furthermore, the invention relates to a method as described above, characterized in that the polyamide molding a filler and / or reinforcing material content in the range of 30 to 90 wt .-%, in particular from 30 to 80 wt .-%, preferably 30 to 50 wt .-%, further preferably from 50 to 90 wt .-%. The data in% by weight relate to the total weight of the polyamide molding.

Furthermore, the present invention relates to the use of a composition (C) obtainable by a process as described above for producing a polyamide molding, in particular a filler-containing and / or fiber-reinforced molding. In particular, the polyamide molding has a filler and / or fiber content in the range of 30 to 90 wt .-%.

Furthermore, the present invention relates to a polyamide molding, in particular a cast polyamide molding, prepared by the process according to the invention.

The polyamide molded parts produced by the process according to the invention can be used in particular as a material for the production of parts of the autocouple series, e.g. Passenger compartment, fenders, as well as auto parts, such as paneling of frames, dashboards and for the interior of passenger compartments. The polyamide moldings can also be used as inliners for tanks, gears, housings, packaging films and coatings.

In principle, the polyamide molded parts produced by the method according to the invention are suitable for any housing for small electrical appliances, such as mobile phones, laptops, iPads or generally plastic articles intended to imitate metal.

The invention is explained in more detail by the following examples. example 1

834 g / h (7062 mmol / h) s (epsilon) -caprolactam, 15 g / h (144 mmol / h) catalyst Bruggolen® C 10 (17% w / ws (epsilon) -caprolactamate in s (epsilon)) Caprolactam) and 51 g / h (14 mmol / h) initiator Bruggolen® C 20 (80% w / w blocked diisocyanate in ε-caprolactam) were in an extruder PTW 16, 130 rpm, nozzle 2 mm, 1, 0 kg / h, mixed at 70 ° C. The mixture was cooled by a cold gas stream (coldfeed 0 ° C). The mixture was granulated under nitrogen at room temperature. One week later, the caprolactam granules thus obtained were injection-molded at a product temperature of 80 ° C in an Arburg 270 S injection molding machine with vertically arranged injection unit. The temperature profile of the cylinder was 60 ° C / 65 ° C / 70 ° C / 75 ° C. The injection time was 0.8 s, the holding pressure time was 2 s. The melt was injected into a mold at 150 ° C die temperature. Thereafter, the polymerization was allowed to proceed for 5 minutes. The resulting polyamide molding was removed from the mold.

The content of residual monomer (caprolactam) of the polyamide product was determined by chromatography. The viscosity number of the polyamide product was determined according to ISO 307 at 5 ° C in 96% sulfuric acid. The resulting polymer contained 0.9 wt% residual caprolactam and had a viscosity number of 195.

Example 2

834 g / h (7062 mmol / h) s (epsilon) -caprolactam, 3000 g / h glass beads, 115 g / h (144 mmol / h) catalyst Bruggolen® C 10 (17% w / ws (epsilon) -caprolactamate in ε-caprolactam) and 51 g / h (14 mmol / h) initiator Bruggolen® C 20 (80% w / w blocked diisocyanate in s (epsilon) -caprolactam) were in an extruder PTW 16, 130 rpm, nozzle 2 mm, 3.0 kg / h, mixed at 70 ° C. The mixture was cooled by a cold gas stream (coldfeed 0 ° C).

The mixture was granulated under nitrogen at room temperature.

One week later, the caprolactam granules thus obtained were injection-molded at a product temperature of 80 ° C. The melt was injected at T = 150 ° C in a mold cavity. Thereafter, the polymerization was allowed to proceed for 5 minutes. The resulting polyamide molding was removed from the mold. The polymer obtained contained 1, 5 wt .-% residual caprolactam and had a viscosity number of 230.

Example 3

The monomer composition prepared according to Example 1 was stored for one month. Thereafter, the polymerization was carried out as described in Example 1. The polyamide obtained contained a residual monomer content of 0.95% by weight of caprolactam and had a viscosity number of 191. It was therefore possible to show that the monomer compositions prepared by the process according to the invention are stable over a long period of time, ie that they can be fully polymerized even after a long time.

Example 4

A composition was prepared as indicated in Example 1, wherein the mixing of the ε-caprolactam, the catalyst and the initiator were carried out in a round bottom flask using a magnetic stirrer. The components were added to the flask in a glove box (protective chamber) under dry nitrogen. After preparation of the composition, the opening of the flask was sealed and removed from the glovebox. The composition was cooled in an ice bath.

The composition was then stored for one week at room temperature. Thereafter, the polymerization was carried out at a temperature of 150 ° C for 10 minutes. The polyamide product had a content of caprolactam residual monomer of 0.85% by weight and a viscosity number of 200.

Examples 5.1 to 5.8: For the following Examples 5.1 to 5.8, the catalyst used was a solution of sodium lactamate in s (epsilon) -caprolactam (catalyst Addonyl® NL, Rhein Chemie), the activator was an oligomer of hexamethylene diisocyanate dissolved in N-methylpyrrolidone (Addonyl® 8108, Rhein Chemie). The components were melted under dry nitrogen and then stirred for 30 seconds in a glass container thermostated at 100 ° C under dry nitrogen. The mixed with the additives s (epsilon) -Caprolactamschmelze was added gravimetrically into a heated to 150 ° C steel mold. Was removed after 5 minutes. The shape and the appearance of the molding as well as the content of residual monomers (s (epsilon-caprolactam) were evaluated. The caprolactam preparations used in the comparative examples were prepared separately under dry protective gas and stored in watertight plastic containers.

Comparative Example 5.1 The following compositions were prepared:

Catalyst melt: 1.5 g of catalyst were stirred in under a protective gas in a mixture of 100 g of melted s (epsilon) -caprolactam from BASF SE at 90 ° C.

Aktivatorschmelze: In a mixture of 100.0 g s (epsilon) -caprolactam were stirred at 90 ° C 1, 0 g activator under inert gas. Both melts were intimately mixed in a flask heated to 90 ° C under dry nitrogen by stirring (30 seconds) and gravimetrically poured into the steel die preheated to 150 ° C. After 5 minutes was removed from the mold. A homogeneous block was obtained. Appearance: good, residual caprolactam 1, 1%

Comparative Example 5.2: Addition of short glass fibers

A catalyst melt was prepared as described in Example 5.1.

Aktivatorschmelze: In a mixture of 100.0 g s (epsilon) -caprolactam were stirred at 90 ° C 1, 0 g activator and 40 g of commercial short glass fibers with size for polyamides (OCV company) under inert gas. Both melts were intimately mixed in a flask heated to 90 ° C under dry nitrogen by stirring (30 seconds) and gravimetrically poured into the steel die preheated to 150 ° C. After 5 minutes was removed from the mold. A homogeneous block was obtained. Appearance: good, residual caprolactam 3.6%, smell of caprolactam

Comparative Example 5.3: no water exclusion

A catalyst melt was prepared as described in Example 5.1.

Aktivatorschmelze: In a mixture of 100.0 gs (epsilon) -caprolactam were stirred at 90 ° C 1, 0 g activator. Both melts were intimately mixed in a flask heated to 90 ° C by stirring (5 seconds) and gravimetrically poured into the steel die preheated to 150 ° C. It was not worked under dry inert gas (nitrogen). After 5 minutes was removed from the mold. A homogeneous block was obtained.

Appearance: poor (streaking, discoloration), residual caprolactam 5.1%, smell of caprolactam

Comparative Example 5.4: Addition of short glass fibers and no water exclusion

A catalyst melt was prepared as described in Example 5.1.

Aktivatorschmelze: In a mixture of 100.0 g s (epsilon) -caprolactam were stirred at 90 ° C 1, 0 g activator and 40 g of commercial short glass fibers with size for polyamides (OCV company).

Both melts were intimately mixed in a flask heated to 90 ° C by stirring (5 seconds) and gravimetrically poured into the steel die preheated to 150 ° C. It was not worked under dry inert gas (nitrogen). After 5 minutes was removed from the mold. A homogeneous block was obtained.

Appearance: very poor (streaking, yellowing), residual caprolactam 8.7%, strong smell of caprolactam.

Example 5.5 101.5 g of solid flaky s (epsilon) -caprolactam, which already contained 1.5 g of catalyst, were mixed with 101.0 g of solid s (epsilon) -caprolactam, which already contained 1.0 g of activator, under protective gas , melted and stirred for 5 seconds.

The melt was poured at 90 ° C in the preheated to 150 ° C steel tool. After 5 minutes was removed from the mold. A homogeneous block was obtained. Appearance: good, residual caprolactam 1, 1%

Example 5.6: Addition of short glass fibers during fabrication

101, 5 g of solid flaky s (epsilon) -caprolactam, which already contained 1, 5 g of catalyst, with 141, 0 g solid s (epsilon) -caprolactam, the already 1, 0 g activator and 40 g of commercially available short glass fibers mixed with size for polyamides (OCV), melted and stirred for 5 seconds.

The melt was poured at 90 ° C in the preheated to 150 ° C steel tool. After 5 minutes was removed from the mold. A homogeneous block was obtained.

Appearance: good, residual caprolactam 1, 2%

Example 5.7: Addition of short glass fibers before processing

101, 5 g of solid flaky s (epsilon) -caprolactam, which already contained 1.5 g of catalyst, were mixed with 101.0 g of solid s (epsilon) -caprolactam which already contained 1.0 g of activator and 40 g of commercially available short glass fibers Sizes for polyamides (OCV) mixed, melted and stirred for 5 seconds.

Appearance: good, residual caprolactam 1, 6%

Example 5.8: (only 1 component):

202.5 g of solid flaky s (epsilon) -caprolactam, the already 1, 5 g of catalyst and 1, 0 g activator was melted under inert gas and not stirred.

Appearance: good, residual caprolactam 1, 0%

The examples and comparative examples 5.1 to 5.8 show that better polyamide molded parts can be produced with less effort by the method according to the invention.

The process according to the invention also provides better products by appearance; In addition, most of the smell can be significantly reduced. The latter aspect can be explained with a lower residual content of unreacted monomers.

Claims

claims

A process for preparing a composition (C) comprising the following components: i) at least one monomer (M) selected from lactams and lactones;

ii) at least one catalyst (K);

iii) at least one activator (A); comprising the following steps: a) mixing the components (M), (K) and (A) and optionally further components at a temperature of 50 to 200 ° C; b) cooling the mixture obtained under step a) to a temperature of 0 ° C to 60 ° C;

c) optionally granulating the cooled mixture.

2. The method according to claim 1, characterized in that the composition (C) contains at least one further component selected from fillers and / or reinforcing materials (F), polymers (P) and further additives (Z).

3. The method according to any one of claims 1 or 2, characterized in that as monomer (M) at least one monomer is selected from the group consisting of caprolactam, piperidone, pyrrolidone, laurolactam, and

Caprolactone.

4. The method according to any one of claims 1 to 3, characterized in that as catalyst (K) at least one compound is used selected from the group consisting of sodium caprolactamate, potassium caprolactamate, bromide

Magnesium caprolactamate, chloride magnesium caprolactamate, magnesium biscaprolactamate, sodium hydride, sodium, sodium hydroxide, sodium ethanolate, sodium methoxide, sodium propanolate, sodium butanolate, potassium hydride, potassium, potassium hydroxide, potassium methoxide, potassium ethanolate, potassium propoxide and potassium butanolate.

5. The method according to any one of claims 1 to 4, characterized in that as activator (A) at least one compound is used selected from the group consisting of aliphatic diisocyanates, aromatic Diisocyanates, polyisocyanates, aliphatic diacid halides and aromatic diacid halides.

A method according to any one of claims 1 to 5, characterized in that the cooling of the mixture in step b) to a temperature of 0 ° C to 60 ° C within a period of 1 to 60 seconds.

Process for the preparation of a polyamide molding by anionic polymerization, in which at least one monomer (M1) selected from lactams and lactones is used for the polymerization, which has been processed to granulate with at least one additive (X1) before the beginning of the polymerization, and in which the granules containing at least one monomer (M1) are then polymerized, wherein the mixture of monomer (M1) with additive (X1) is optionally selected in solid form or melt before or during the polymerization with at least one further monomer (M2) from lactams and lactones and / or at least one other additive (X2) is mixed.

A process for producing a polyamide molded article according to claim 7, wherein the at least one monomer (M1) and the optional further monomer (M2) are each independently selected from the group comprising lactams having 6 to 16 carbon atoms in the ring.

A process for producing a polyamide molding according to any one of claims 7 or 8, wherein the processing of the at least one monomer (M1) with the at least one additive (X1) to a granulate by mixing the components in a dry state.

A process for producing a polyamide molded article according to any one of claims 7 to 9, wherein a composition (C) obtainable by a process according to any one of claims 1 to 6 is polymerized by heating at a temperature of 120 to 250 ° C.

A process for producing a polyamide molded article according to claim 10, comprising the following steps: i) melting the composition (C) at a temperature of 50 ° C to 200 ° C; j) filling the molten composition (C) into a tool cavity; k) polymerization of the composition (C) by heating to a temperature of 120 ° C to 250 ° C.

A process for producing a polyamide molding according to any one of claims 7 to 11, characterized in that the polyamide molding has a filler and / or reinforcing material content in the range of 30 to 90 wt .-%.

Use of a composition (C) obtainable by a process according to any one of claims 1 to 6 for the preparation of a polyamide molding.

14. Polyamide molding obtainable by a process according to one of claims 7 to 12.